城市道路绿地微气候效应的ENVI-met模拟及景观绩效研究

Urban roads are one of the most closely related to Spaces of human activities, occupying nearly 1/4 of the urban space.，have become the important source of urban environmental degradation and major disaster area. Urban road green space is an important strategy to improve the microclimate, but the existing research results are scattered, there is no clear definition and systematic research on urban road microclimate. In this study, road microclimate is summarized as temperature, humidity, wind and particulate matter, and ENVI-met and i-Tree Streets models of modern simulation technology are applied to scientifically and quantitatively evaluate the microclimate effect and economic value of road green space, so as to obtain the planning and design strategy of road green space to improve the microclimate.. The research takes the urban road space microclimate as the research object, and mainly studies the following four aspects：(1)Construction of theoretical factors for road green space and microclimate elements；(2)Measured research on the influence of road green space on microclimate and determination of its factor threshold；(3) Research on the impact of urban road green space planning and design on microclimate based on ENVI-met simulation；(4) Research on landscape performance based on i-Tree Streets model. The research results will obtain the theoretical factors of urban road green space planning and design to improve the microclimate, reveal the ability of urban road green space to improve the microclimate, combine the planning and design scenario with landscape performance evaluation, and realize the economic evaluation of green space and the optimization of planning and design scheme.

城市道路是与人类活动最紧密相关的空间之一，占据着近1/4的城市面积，是当今城市环境恶化的重要源头和重灾区。城市道路绿地是改善微气候的重要策略，但目前并未对城市道路微气候有明确定义和系统研究。本研究将道路微气候归纳温度、湿度、风、颗粒物，运用现代模拟技术ENVI-met、i-Tree streets模型，科学定量评价道路绿地微气候效应及其经济价值，探究改善微气候的道路绿地规划设计策略。. 研究从①道路绿地空间及微气候要素理论因子构建；②道路绿地空间对微气候影响的实测及因子阈值确定；③基于ENVI-met模拟的城市道路绿地规划设计对微气候影响研究； ④基于i-Tree streets模型的景观绩效研究；四个方向展开。研究结果将得出改善微气候的城市道路绿地规划设计理论因子，揭示城市道路绿地改善微气候的能力，将规划设计情景与景观绩效评估相结合，实现绿地空间经济评估及规划设计方案优化。

建筑环境中的绿色基础设施，被认为是改善人居环境质量的一种潜在城市规划解决方案。城市道路是与人类活动最紧密相关的空间之一，是城市环境恶化的重要源头和重灾区。现有城市道路绿地规划设计，缺乏对微气候改善视角下的有效格局和策略。研究在“绿色宜居”“存量规划”的时代背景下，基于ENVI-met模拟技术手段，实现影响道路空间微气候因子的多情景方案模拟，探究城市道路绿色空间改善微气候效应的有效优化策略。 . 研究表明：1）实测得到道路微气候时空分布特征：温度日变化规律，武汉珞喻路温度高峰出现在下午16点左右；PM日变化规律，早8点晚18点两个高峰。微气候空间分布特征：从断面看，温度由中央到两遍下降趋势，人行道比道路中央无遮阴情况下温度日均值降低了1.7℃，降温幅度-4.76%；从道路16:00横断面PM2.5值来看，由道路中央至边缘呈现递减趋势，人行道比道路中央无遮阴情况下日均值降低了6.72μg/m3，消减幅度-25.01%。2）模拟结果表明，增加绿地率有降低人行道温度、消减颗粒物污染的作用，40%＞30%＞20%。在绿地断面板带式选择上，随板带式增多，降温效益越好；消减颗粒物效益上，三板四带和一板两带式优于两板三带和四板五带式；以降温为主的街道，选择四板五带式绿带布局，以消减颗粒物为主的街道，以三板四带式布局为宜。综合降温及消减颗粒物，三板四带式是最有益于降温及消减颗粒物的选择。4）对植物配置来说，加大行道树冠幅、树高、间距，有利于道路降温；绿篱对温度作用不显著。植物配置对PM作用，绿篱的作用更显著，可有效降低PM。街道峡谷中减小行道树冠幅，有利于消减道路PM；开放道路中，增加树高对降低PM的效果显著。研究可为道路绿地规划设计改善微气候效益提供科学依据和参考。